1. Field of the Invention
This invention relates to a steering head for a bicycle, particularly a motor-assisted bicycle, comprising a bearing sleeve and a mounting shaft which extends in the bearing sleeve and a main frame member which extends rearwardly and downwardly from the steering head and consists preferably of two half-shells which are welded together.
2. Description of the Prior Art
The main frame member extends rearwardly and downwardly from the steering head and either joins the seat tube before the rear wheel or is continued by the seat pillar. This main frame member leaves behind the steering head a free space so that the rider can conveniently mount the vehicle. In the previous practice, the bearing sleeve has been secured to the forward end of the main frame member and has usually been welded to or into the main frame member whereas the mounting shaft which extends through the bearing sleeve belongs to the fork head of the front wheel fork and in most cases is connected to the blades of the front wheel fork by upper and lower bridges. For this reason, the main frame member must extend upwardly as far as to the top end of the bearing sleeve, i.e., to a relatively high level below the handlebar, so that the free space which is required for a convenient mounting of the vehicle by the rider is restricted. Another disadvantage resides in that Bowden and electric cables which lead to hand levers, switches and/or instruments mounted on the handlebar cannot extend through the steering shaft into the main frame member but must be exposed at least in part so that they are not protected.
Whereas a design is known in which the bearing sleeve of the steering head forms part of the fork head of the front wheel fork (British Pat. No. 209,921), the mounting shaft of the steering head of that arrangement is held above and below the bearing sleeve by a pair of frame tubes so that the frame must also extend upwardly to the top end of the bearing sleeve and cables cannot be extended in the mounting shaft. When it is desired to remove the front wheel fork, the upper pair of frame tubes must be disconnected from the mounting shaft of the steering head before the bearing sleeve can be pulled off upwardly. This is relatively complicated. Besides, a relatively expensive tubular frame is required.